The Dreamliner's use of lightweight composite materials to greatly improve fuel economy has made it a big seller in Asia and the Middle East, where long-haul flights account for much of an airline's business.

United Airlines, which has six Boeing 787 aircraft, is the only U.S. airline to take delivery of the Dreamliner so far. It will cost the airline about $2.8 million to implement the fix, according to the FAA's Federal Register filing.

The company plans to begin domestic flights using the 787 in May and possibly launch the Denver-Narita, Japan, route on June 10.